svn commit: r321678 - head/usr.sbin/prometheus_sysctl_exporter

[Ed Schouten]

Author: ed
Date: Sat Jul 29 08:35:07 2017
New Revision: 321678
URL: https://svnweb.freebsd.org/changeset/base/321678

Log:
  Be a bit more liberal about sysctl naming.
  
  On the systems on which I tested this exporter, I never ran into metrics
  that were named in such a way that they couldn't be exported to
  Prometheus metrics directly. Now it turns out that on systems with NUMA,
  the sysctl tree contains metrics named dev.${driver}.${index}.%domain.
  For these metrics, the % in the name is problematic, as Prometheus
  doesn't allow this symbol to be used.
  
  Remove the assertions that were originally put in place to prevent the
  exporter from generating malformed output and add code to deal with it
  accordingly. For metric names, convert any unsupported character to an
  underscore. For label values, perform string escaping.
  
  PR:		https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=221035
  Reported by:	lifanov@

Modified:
  head/usr.sbin/prometheus_sysctl_exporter/prometheus_sysctl_exporter.c

Modified: head/usr.sbin/prometheus_sysctl_exporter/prometheus_sysctl_exporter.c
==============================================================================
--- head/usr.sbin/prometheus_sysctl_exporter/prometheus_sysctl_exporter.c	Sat Jul 29 08:24:51 2017	(r321677)
+++ head/usr.sbin/prometheus_sysctl_exporter/prometheus_sysctl_exporter.c	Sat Jul 29 08:35:07 2017	(r321678)
@@ -1,5 +1,5 @@
 /*-
- * Copyright (c) 2016 Nuxi, https://nuxi.nl/
+ * Copyright (c) 2016-2017 Nuxi, https://nuxi.nl/
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -32,6 +32,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/sysctl.h>
 
 #include <assert.h>
+#include <ctype.h>
 #include <err.h>
 #include <errno.h>
 #include <math.h>
@@ -384,11 +385,12 @@ oidname_print(const struct oidname *on, const struct o
 	label = on->labels;
 	for (i = 0; i < on->oid.len; ++i) {
 		if (*label == '\0') {
-			assert(name[strspn(name,
-			    "abcdefghijklmnopqrstuvwxyz"
-			    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
-			    "0123456789_")] == '\0');
-			fprintf(fp, "_%s", name);
+			fputc('_', fp);
+			while (*name != '\0') {
+				/* Map unsupported characters to underscores. */
+				fputc(isalnum(*name) ? *name : '_', fp);
+				++name;
+			}
 		}
 		name += strlen(name) + 1;
 		label += strlen(label) + 1;
@@ -404,15 +406,18 @@ oidname_print(const struct oidname *on, const struct o
 	separator = '{';
 	for (i = 0; i < on->oid.len; ++i) {
 		if (*label != '\0') {
-			assert(name[strspn(name,
-			    "abcdefghijklmnopqrstuvwxyz"
-			    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
-			    "0123456789_-")] == '\0');
 			assert(label[strspn(label,
 			    "abcdefghijklmnopqrstuvwxyz"
 			    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 			    "0123456789_")] == '\0');
-			fprintf(fp, "%c%s=\"%s\"", separator, label, name);
+			fprintf(fp, "%c%s=\"", separator, label);
+			while (*name != '\0') {
+				/* Escape backslashes and double quotes. */
+				if (*name == '\\' || *name == '"')
+					fputc('\\', fp);
+				fputc(*name++, fp);
+			}
+			fputc('"', fp);
 			separator = ',';
 		}
 		name += strlen(name) + 1;